Silica Gel Research Articles

Advanced HPTLC Method Development for Silibinin Analysis in Nanoformulated Scaffolds: A Box–Behnken Approach

ABSTRACTIntroductionSilibinin (silybin), a bioactive component derived from the seeds of milk thistle (Silybum marianum), is recognized for its diverse pharmacological properties, including antioxidant, anti‐inflammatory, and hepatoprotective effects. Given its therapeutic significance, accurately quantifying silybin in various formulations is essential. High‐performance thin‐layer chromatography (HPTLC) is a powerful analytical technique frequently used for this purpose. In this study, an HPTLC method was validated according to the International Council for Harmonization (ICH) guidelines to determine the concentration of silybin. The design of experiments (DoE), specifically the Box–Behnken design, was employed to optimize and understand the influence of critical method variables.MethodologyThe HPTLC method validation was performed using silica gel F254 HPTLC plates. The variables investigated included the composition of the mobile phase (% v/v), saturation time (minutes), and temperature in degree Celsius (°C), with the Box–Behnken design for optimization. The mobile phase consisted of chloroform, acetone, and formic acid in a 7:2:1 (v/v) ratio. Both the formulated scaffold and standard drug were applied to the plates, which were then processed in a twin chamber. After development, the plates were scanned at 288 nm using the Camag TLC Scanner IV with Vision CATS software.ResultsThe validated HPTLC method demonstrated a strong linear relationship within the silybin concentration range of 2–10 μg/mL. The limit of detection (LOD) and limit of quantification (LOQ) for silybin were determined to be 0.469 and 1.423 μg/mL, respectively. Recovery studies indicated that the method provided accurate quantification, with recovery rates ranging from 97.53% to 99.82%. These results confirm the method's high accuracy, outstanding linearity, and reliability for the quantification of silybin in formulations.ConclusionThe validated HPTLC method proved to be a reliable analytical tool for the quantification of silybin in various formulations, particularly those containing polymers. The method's strong linearity, precision, and accuracy align with the ICH guidelines, making it suitable for routine analysis in quality control laboratories. The use of the Box–Behnken design for method optimization highlights the importance of systematic experimentation in achieving robust analytical outcomes.

Stability of immobilized L-arginine deiminase from Penicillium chrysogenum and evaluation of its anticancer activity

The aim of the present work was to immobilize L-arginine deiminase on suitable supports such as chitosan, alginate, and silica gel to study its stability. Additionally, the study aims to investigate the anticancer effects of the free purified enzyme on hepatocellular carcinoma (Hep-G2) and breast cancer (MCF-7) cell lines. L-arginine deiminase (ADI: EC 3.5.3.6) was immobilized on chitosan, Ca-alginate, and silica gel, with immobilization efficiencies of 89.0%, 72.8%, and 66.5%, respectively. The optimal immobilization time for the highest efficiency was 4 h. Increasing the concentration of glutaraldehyde improved the immobilization efficiency of ADI on chitosan. The chitosan-immobilized ADI retained about 45% of its activity after 8 cycles. The optimal pH values were 6 for the free purified ADI and 7 for the chitosan-immobilized ADI. The optimal temperature increased from 40 °C for the free enzyme to 45 °C after immobilization. The activation energies for the free and chitosan-immobilized enzymes were 71.335 kJ/mol and 64.011 kJ/mol, respectively. The Km values for the free and chitosan-immobilized ADI were 0.76 mM and 0.77 mM, respectively, while the Vmax values were 80.0 U/mg protein for the free ADI and 71.4 U/mg protein for the chitosan-immobilized ADI. After 30 days of storage at 4 °C, the residual activities were 40% for the free purified ADI and 84% for the chitosan-immobilized ADI. At 25 °C, the residual activities were 10% for the free ADI and 75% for the chitosan-immobilized ADI. The chitosan-immobilized ADI exhibited significantly higher stability against proteases such as pepsin and trypsin compared to the free enzyme. The purified ADI also demonstrated enhanced potential anticancer effects and significant cytotoxicity against the Hep-G2 and MCF-7 tumor cell lines compared to doxorubicin. These findings suggest that purified ADI has potential as an anticancer agent, though further in-depth studies are required.

Revolutionary ZVI-Entrapped Sol–Gel Silica Matrices: Efficient Catalytic Reduction of High-Concentration Halo-Organic Compounds—Addressing Bromoacetic Acid Contamination in Industrial Wastewaters

The de-halogenation of highly concentrated halo-organic compounds using Zero Valent Iron entrapped in silica matrices as a catalyst was investigated. This study aimed to evaluate the effectiveness of the Zero Valent Iron-entrapped organically modified silica matrices in transforming highly concentrated hazardous halogenated compounds into environmentally benign materials in the presence of BH4−. The Zero Valent Iron-entrapped silica gel matrices were synthesized using the sol–gel method. The de-halogenation products were analyzed using high-performance liquid chromatography. The results suggest that the Zero Valent Iron-entrapped silica matrices are effective catalysts in the de-halogenation reaction of halo-organics by BH4− with 100% efficiency. The current work also highlights the complete de-bromination of harmful wastewater generated by the bromoacetic acid manufacturing industry using Zero Valent Iron-entrapped silica matrices. Therefore, Zero Valent Iron-entrapped silica matrices can be considered potential candidates for the catalytic removal of highly concentrated halo-organic compounds from contaminated water. This technology can play a crucial role in reducing the environmental impact of hazardous substances.

Effect of Exchange Dynamics on the NMR Relaxation of Water in Porous Silica.

The interaction of molecules, in particular, water, with solid interfaces has been studied by a multitude of methods, among them nuclear magnetic resonance spin relaxation. The frequency dependence of the relaxation times follows patterns that have been interpreted in terms of the molecular orientation and dynamics. Several different model approaches could successfully explain limiting cases of 1H relaxation dispersion in systems with rigid surfaces such as silica gel or glass, but none of them can reproduce the relaxation of both 1H and 2H nuclei, which differ in their respective relaxation mechanisms, dipolar vs quadrupolar. From detailed studies of the dynamics of hydration of water in biological materials, the importance of hydrogen and molecular exchange to the longitudinal relaxation time of T1 was demonstrated. In this work, exchange times of both H2O and D2O in hydrophilic silica gel are varied in a controlled fashion in a wide range using disodium hydrogen phosphate, and the effect of physical exchange on spin relaxation is quantified for the first time in such systems using the exchange-mediated reorientation model.

A methodology for selection of solid desiccants in energy recovery ventilators

Controlling indoor humidity levels is essential for maintaining acceptable indoor air quality in buildings. The use of energy recovery ventilators (ERVs) is an energy-efficient way to regulate indoor air humidity. Fixed-bed regenerators and rotary wheels are widely used ERVs because of their high sensible and latent effectiveness. These ERVs are made of desiccant-coated substrates, which enable them to transfer moisture between the supply and exhaust air streams. However, the moisture transfer ability of ERVs depends on the physiochemical and sorption properties of desiccants. Extensive, full-scale experiments are required to determine the best desiccant material for these systems. This paper presents a simplified method of selecting suitable desiccant materials for ERVs. The methodology involves important characterization methods, literature correlations for performance prediction, and cost-effective testing methods prior to full-scale testing, and full-scale test methods are discussed in detail. Furthermore, the performance of a few newly derived materials is evaluated and compared with that of conventional desiccants such as silica gel and molecular sieves. The highest latent effectiveness was obtained for composite of super absorbent polymer (SAP) with potassium formate (SAP-HCO2K-50 %), all-polymer porous solid desiccant (APPSD) and metal organic framework (MOF)–MIL–101 (Cr), followed by activated carbon fibre felt (ACF) Silica sol-LiCl30, SAP, silica gel, MOF–303, and molecular sieve. Researchers and manufacturers would benefit from the proposed methodology and presented data in developing new desiccant materials for ERV applications.

Ionogels in Aqueous Media: From Conductometric Probing of the Ionic Liquid Washout to the Design of More Stable Materials

Although the most promising applications of ionogels require their contact with aqueous media, few data are available on the stability of ionogels upon exposure to water. In this paper, a simple, easy-to-setup and precise method is presented, which was developed based on the continuous conductivity measurements of an aqueous phase, to study the washout of imidazolium ionic liquids (IL) from various silica-based ionogels immersed in water. The accuracy of the method was verified using HPLC, its reproducibility was confirmed, and its systematic errors were estimated. The experimental data show the rapid and almost complete (>90% in 5 h) washout of the hydrophilic IL (1-butyl-3-methylimidazolium dicyanamide) from the TMOS-derived silica ionogel. To lower the rate and degree of washout, several approaches were analysed, including decreasing IL content in ionogels, using ionogels in a monolithic form instead of a powder, constructing ionogels by gelation of silica in an ionic liquid, ageing ionogels after sol–gel synthesis and constructing ionogels from both hydrophobic IL and hydrophobic silica. All these approaches inhibited IL washout; the lowest level of washout achieved was ~14% in 24 h. Insights into the ionogels’ structure and composition, using complementary methods (XRD, TGA, FTIR, SEM, NMR and nitrogen adsorption), revealed the washout mechanism, which was shown to be governed by three main processes: the diffusion of (1) IL and (2) water, and (3) IL dissolution in water. Washout was shown to follow pseudo-second-order kinetics, with the kinetic constants being in the range of 0.007–0.154 mol−1·s−1.

An improved synthesis of alkyl AMP esters

Enzymes belonging to the Acyl-CoA/NRPS/Luciferase (ANL) superfamily of enzymes, are significant targets in drug development. One member of this superfamily is Acetyl-CoA Synthetase (ACS). This enzyme is an emerging target for the treatment of various infectious diseases and cancer. Alkyl AMP esters have emerged as potent inhibitors of ACS. Previous methods for synthesizing these esters often involved water-based reactions or necessitate purification through reverse phase prep-HPLC or ion-exchange chromatography. To address these challenges, we developed a new approach utilizing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) to couple 5′-adenylic acid to the corresponding alcohol, utilizing triethylamine as the base. This method yielded primary, secondary, unsaturated, and cyclic alcohols in excellent yields. Importantly, we optimized the reaction conditions to achieve excellent yield and purity without the need for reverse phase prep-HPLC or ion exchange chromatography. Instead, purification was achieved through silica gel chromatography using Biotage ® Sfar spherical silica gel.

Mechanism of organic additives-induced carbonation activators on affecting cement mortars

In this study, we investigated the impact of introducing an in-situ activator, produced by carbonating cement particles in an aqueous solution, on the properties of cement mortars through secondary mixing. Two organic additives, ethylenediaminetetraacetic acid (EDTA) and glutamic acid (GLTA), were employed to enhance the leaching of calcium ions during carbonation, thereby improving the carbonation efficiency. A suite of characterization techniques revealed that the presence of organic additives could refine the carbonated particles and influence the morphology. The carbonated activators generated by this process were rich in silica gel and various polymorphic forms of calcium carbonate. These components, serving as fillers and nucleation for cement hydration, significantly accelerated the hydration process of cement mortar and promoted the formation of carboaluminate in the secondary mixing process. This approach effectively decreased the porosity of the cement mortar, refined the pore structure, and enhanced the mechanical strength.

Alkaline activation via in-situ caustification of one-part binders of composite precursors of waste glass and limestone

Mixtures of powders of waste glass (WG), limestone (LS), Na2CO3 and CaO were used to formulate novel one-part in situ alkali-activated cement (WG-AAC). The in-situ interaction Na2CO3-CaO-H2O promoted the formation of CaCO3 and NaOH, which promoted the WG and LS dissolution and influenced the micro- and molecular features of the resulting cementitious products. Pastes and mortars developed 1-year strengths of up to 29 MPa and were stable underwater. Characterization by XRD, SEM, EDS, and 29Si-NMR indicated that a Na2CO3:CaO ratio close to 1:1 resulted in polymerized C-S-H, CaCO3, silica gel, and Ca-modified silica gel, which were intimately intermixed and possibly crosslinked through Q3 bonds. Such phases interacted synergistically improving the underwater stability of the WG-AAC, indicating that in-situ caustification is a suitable and practical alkaline activation for SiO2-rich precursors.

A high-performance thin-layer chromatography densitometric method for the separation of isomeric ceftriaxone in powder for injection formulation

The aim of this study was to develop and validate a High-Performance Thin Layer Chromatographic (HPTLC) method for simultaneous determination of ceftriaxone and ceftriaxone e-isomer in powder for injection formulation. Ceftriaxone sodium injection is an antibiotic that used globally. It has Z/E geometrical conformation, in which ceftriaxone sodium and 3 ene-isomer have Z- conformation while (E)-isomer has E- conformation and the potential toxicity of ceftriaxone (E)-isomer has been reported. Thus, to safeguard the public health, a simple and easy to use, rapid and reliable method was developed for qualitative and quantitative determination of ceftriaxone sodium and its (E)–isomer. Samples were applied on HPTLC glass plates precoated with silica gel 60F254 by using Linomat semi-auto sampler. Separation was carried out using acetone, triethyl amine, water, chloroform and ethyl acetate as a mobile phase in different ratios. The Rf values of separated compounds were 0.51 ± 0.01 and 0.62 ± 0.01 for ceftriaxone sodium and ceftriaxone (E)-isomer respectively. The method was validated by studying Specificity, Linearity, Accuracy, Precision, Robustness, Limit of Detection (LOD) and Limit of Quantification (LOQ) and Solution stability. The developed method was successfully, sensitive, simple, precise, accurate, robust and applicable for the simultaneous determination of ceftriaxone sodium and ceftriaxone (E)-isomer in powder for injection formulation.

Deep dehumidification characteristics of a silica gel coated cross-flow heat exchanger with a circulating blowing loop

Solid desiccant dehumidification systems offer an effective and energy-efficient alternative for deeply dehumidifying air. Desiccant coated heat exchangers (DCHEs), a type of solid desiccant dehumidification system, have garnered attention due to their ability to eliminate adsorption heat and thereby enhance dehumidification capacity, unlike desiccant wheels that perform adiabatic dehumidification. This study introduces a silica gel coated cross-flow DCHE equipped with a circulating blowing loop for deep dehumidification applications. A two-dimensional numerical model is developed to simulate deep dehumidification behavior of the DCHE. Parametric analysis is performed to explore the dehumidification characteristics under various conditions, setting different volume fractions ω of blowing loop air. Results indicate that the DCHE can effectively reduce the moisture content of humid air to a deep dehumidification threshold of 6.2 g/kg. Additionally, dehumidification capacity can be increased by incorporating a circulating blowing loop. The influence of process air velocity, cooling air velocity, process air humidity ratio, regeneration air temperature, and air channel length on the dehumidification performance are analyzed, focusing on metrics such as minimum outlet air humidity ratio Ya1,ad,out_min, effective deep dehumidification time teff, moisture removal capacity MRC and dehumidification coefficient of performance DCOP. It is determined that the regeneration air temperature should be raised to 80 °C to ensure deep dehumidification, and an air channel length of 0.2 m is optimal.

Sustainable Biological Production and Innovative Purification of the 1,3-Propanediol from Glycerol Fermentation Broth via Resin Adsorption

The study focuses on enhancing the production and purification of 1,3-Propanediol (1,3-PDO), a versatile compound used across various industries. Conventionally, 1,3-propanediol (1,3-PDO) has been derived from petroleum-based feedstocks through chemical processes, which pose significant cost and environmental concerns. This has prompted the exploration of sustainable biological production methods using microorganisms to ferment glycerol, the main by-product of palm oil transesterification in biodiesel production. However, downstream purification remains complex and inefficient. To address this, our study introduces a novel and economically viable purification strategy for 1,3-PDO derived from a semi-industrial fermentation broth. The purification process involves pre-treatment steps: centrifugation, flocculation with chitosan, decolorization with activated charcoal, and broth concentration via rotary evaporation. These steps resulted in a transparent broth with a minimal 6% loss of 1,3-PDO. Various resin types, including Sulfonated Styrene Divinylbenzene (S-SDVB) and Styrene Divinylbenzene (SDVB) ion exchange resins in different ionic forms in addition to silica gel resin, were evaluated for their effectiveness in separating 1,3-PDO in terms of recovery and purity. A key aspect of our study is the detailed investigation of the equilibrium adsorption characteristics of SDVB and S-SDVB resins, each with different ion forms. This analysis provides insights into how resin modifications affect the separation process, aiming for higher yields and purities of 1,3-PDO. The findings revealed that the Langmuir adsorption isotherm fits experimental data. Column chromatography experiments showed SDVB resins' deficiencies in separating 1,3-PDO from other components, while silica gel resin achieved a recovery rate exceeding 96% purity and approximately 80% overall recovery. Notably, the Ca2+ form of S-SDVB resin achieved high recovery (95-100%) and purity (91-93%) in both synthetic and real fermentation broths, addressing biodiesel challenges and proposing a solution for large-scale microbial 1,3-PDO production.

Antitrypanosomal and antileishmanial activity of compounds from some Nigerian plants

Ten compounds, six extracts and five fractions obtained from three Nigerian plants were assayed for their in vitro antitrypanosomal and antileishmanial activities. Each plant was extacted with hexane, ethyl acetate, and methanol. Isolated compounds were characterized and identified based on their NMR chemical shifts and comparison to literature reports. The crude extracts, fractions and isolated compounds were tested against the kinetoplastid parasites: bloodstream forms of Trypanosoma brucei Lister 427WT and the derived multi-drug resistant clone B48, and promastigote forms of Leishmania mexicana cas9/T7 and the derived clone cas9ΔNT1. Column chromatography of the extracts using silica gel yielded ten compounds identified as curzerenone, epi-curzerenone, chloranthene F, isofuranodienone, 8(17)-12E-labdadiene-15, 16-dial and 15-hydroxy-8(17),12E-labdadiene-16-al from Siphonochilus aetiopicus, lupeol, linalolic acid and spinasterone from Calliandra portoricensis, and abruquinone B from Abrus precatorius. The assay results showed that the Siphonochilus aetiopicus and Calliandra portoricensis crude extracts, fractions and compounds displayed moderate activity against the Trypanosoma brucei brucei but showed less activity against Leishmania mexicana. Abrus precatorius crude extract, fraction, and isolated compound exhibited only weak trypanocidal and leishmanicidal activities against both kinetoplastid parasites tested. These findings have provided evidence for the use of Siphonochilus aetiopicus and Calliandra portoricensis in traditional medicine relating to parasitic diseases.

Antibacterial Polyketides from the Plant Endophytic Fungus Fusarium sp.

Background: Endophytic fungi have been recognized as new sources of natural products with a variety of biological activities, providing lead compounds for drug discovery and development. Objective: The objective of this study is to isolate and identify the secondary metabolites from the plant endophytic fungus Fusarium sp. HJY2 and evaluate their antibacterial activities. Methods: The compounds were isolated and purified by the methods of silica gel column chromatography, Sephadex LH-20 gel chromatography, and semi-preparative high performance liquid chromatography (HPLC). The structures of the isolated compounds were elucidated by comparing the NMR and MS spectroscopic data with those of pieces of literature. The antibacterial activities were evaluated by the broth microdilution method. Results: Seven polyketides were isolated from the fermented extracts of the fungus Fusarium sp. HJY2 and identified as sydowinol (1), dihydrolateropyrone (2), 13-oxo-9Z,11E-octadecadienoic acid (3), (E)-ferulic acid (4), 4-hydroxyphenylacetic acid (5), methyl 2-(2-hydroxyphenyl)acetate (6) and 4-hydroxy-3-methoxyacetophenone (7). Compound 3 exhibited moderate antibacterial activities against Bacillus subtilis, Mycobacterium smegmatis, Ralstonia solanacearum, and Xanthomonas campestris pv. campestris with MIC values of 40, 40, 80 and 40 μg/mL, respectively. Conclusion: Seven compounds were isolated from the plant endophytic fungus Fusarium sp. HJY2. Compound 1 was isolated from the Fusarium genus for the first time. Compound 3 showed moderate antibacterial activities.

Isolation, Purification, and Antioxidant Activity of Polyphenols from Cynanchum auriculatum Royle ex Wight

Cynanchum auriculatum Royle ex Wight (CA) is a traditional medicinal and edible plant in China. This study aimed to isolate and characterize the phenolic compounds of C. auriculatum to identify its main antioxidant constituents. Polyphenols were extracted using an ultrasound-assisted ethanol extraction method, followed by partitioning with ethyl acetate. The ethyl acetate extract was then purified through thin-layer chromatography, silica gel column chromatography, and reverse-phase silica gel column chromatography. Three monomeric compounds—cynandione A (I), 2,5-dihydroxyacetophenone (II), and radix piperacanthone (III)—were identified through their physical and chemical properties, UV and IR spectra, and liquid chromatography–mass spectrometry (LC-MS/MS). Vitamin C (VC) and 2,4-dihydroxyacetophenone were used as controls to evaluate the antioxidant potential of the two most abundant monomers. Antioxidant assays demonstrated that 2,5-dihydroxyacetophenone and cynandione A exhibited strong antioxidant activity at lower concentrations, whereas 2,4-dihydroxyacetophenone showed significantly weaker activity. Furthermore, cynandione A displayed superior cellular antioxidant activity compared to 2,5-dihydroxyacetophenone, indicating its potential as a promising bioactive compound. In conclusion, this study provides valuable insights into the phenolic composition of C. auriculatum and highlights cynandione A as a key antioxidant, paving the way for future research on its therapeutic applications.

Hydrate management strategies for CO2 injection into depleted gas reservoirs

Sequestering CO2 in depleted gas reservoirs using carbon capture, utilization, and storage technologies has emerged as a viable strategy for mitigating global carbon emissions. However, CO2 hydrate formation during injection processes is challenging and poses a risk to the operational integrity and efficiency of sequestration projects. This study investigated CO2 hydrate formation dynamics within silica gel environments that closely mimicked the median pore size of natural sandstone reservoirs, particularly targeting depleted gas fields in the East Sea of Korea. Integrating kinetic insights into experimental hydrate formation assessments and molecular dynamics simulations provided a comprehensive understanding of the CO2 hydrate formation mechanisms, as well as the formation dynamics and stability of the CO2 hydrates. For example, the hydrate formation kinetics were significantly reduced in the small pores, suggesting the feasibility of implementing more economical hydrate inhibitor injection strategies during CO2 injection. Moreover, this study evaluated the inhibitory effects of NaCl and methanol on CO2 hydrate stability by accurately measuring the three-phase (H-Lw-V) equilibria and employing silica gels (6 nm pore size). The presence of methanol and amorphous silica significantly impacted hydrate formation, with methanol potentially influencing the local structure around the hydrate phase and silica hindering hydrate growth through dynamic interactions with CO2 molecules. In addition, we elucidated the complex interplay between CO2, water, and methanol (hydrate inhibitor) within the constrained environments of porous media, offering strategic insights for the development of effective CO2 injection and sequestration strategies. Integrating molecular-level observations with real-world geological modeling presents a novel methodology for enhancing the safety, efficiency, and environmental sustainability of carbon capture and storage operations. The findings of this study provide critical insights into hydrate phase behavior, highlighting the importance of precise equilibrium determination under simulated reservoir conditions to effectively anticipate and mitigate hydrate formation challenges.

Screening and Selection of a New Medium and Culture Conditions for Diosgenin Production via Microbial Biocatalysis of SYt1

Diosgenin (DSG) is a phytosterol saponin mainly found in Dioscorea zingiberensis C.H. Wright. It has shown promising results in treating various diseases such as cancer, diabetes, arthritis, asthma, and cardiovascular diseases. Diosgenin is also an important medicinal chemical for synthesizing various steroid medicines. The production of diosgenin by acid hydrolysis generates a large amount of wastewater, leading to severe environmental pollution. However, producing diosgenin through microbial fermentation can effectively reduce environmental pollution. Numerous studies have demonstrated that various microorganisms can produce diosgenin via solid-state fermentation. Nevertheless, due to the complexity, high maintenance costs, uneven heat production, and other characteristics of solid-state fermentation, it is not commonly used in the industrial production of diosgenin. In contrast, liquid fermentation offers advantages such as simple operation, easy maintenance, and stable fermentation, making it more suitable for the industrial production of diosgenin. However, few studies have focused on producing diosgenin using liquid fermentation. In this study, endophytic Bacillus licheniformis SYt1 was used to produce diosgenin via liquid fermentation, with Dioscorea tuber powder as a substrate. Soxhlet extraction and silica gel column chromatography were employed to identify the diosgenin from the liquid fermentation products. Suitable fermentation conditions were screened and identified. The environmental variables that significantly affect the diosgenin yield were determined by the Plackett–Burman design (P-BD) with eight factors. The three factors (peptone, yeast extract powder and inorganic salt) with the greatest influence on the diosgenin yield were selected and further optimized using a response surface methodology (RSM). The final culture conditions were determined to be 35.79 g/L of peptone, 14.56 g/L of yeast extract powder, and 1.44 g/L of inorganic salt. The yield of diosgenin under these conditions was 132.57 mg/L, which was 1.8 times greater than the yield under pre-optimization conditions. This effective, clean, and promising liquid fermentation method possesses the potential to replace the traditional acid hydrolysis method for the industrial production of diosgenin.

Synthesis and characterization of copper tartrate Crystals grown in silica gel

Copper tartrate crystals were grown by the ‘Single diffusion’ method in silica gel by gel growth technique. Optimum conditions of crystal growth such as pH, specific gravity, aging period of gel, concentration of reactants in gels were determined by varying them. The unit cell of a grown crystal is Orthorhombic as characterized using Powder X-Ray diffraction. The Fourier transform infrared spectrum in the range 400–4,000 cm-1 were recorded and the vibrational bands corresponding to functional groups is assigned. FTIR has confirmed the carboxyl as functional group and the other bonds between atoms. XPS has concluded paramagnetic nature and the presence of cu2+ ion.

Electro-optical and thermal characterization of copper tartrate crystals grown in silica gel

Copper Tartrate crystals were grown by Gel Growth technique by single diffusion. Silica gel of Optimum specific gravity was set with tartaric acid at optimum pH and aging period. Band gap of copper tartrate crystal is determined using UV-Visible spectroscopy to be 5.24 eV. In PL spectra broad peak is observed at nearly 367.44186 nm in the range 287 nm to 458 nm along with the sharp, intense transmission maxima peak at wavelength nearly 505.03876 nm which is characteristic of a material composition and electronic band structure. This shows the transparency in UV-visible region and material is a filter in this range .TGA analysis concluded that Copper tartrate has one half water molecule as crystalline water and is stable up to 85.02 0 C.DSC analysis assigns the temperature value 314.5 0C as melting point and apparent enthalpy of fusion determined is 10.18 mW.

Highly oxygenated dihydrostilbenoids and flavones from the aerial part of Glycyrrhiza uralensis and their antimicrobial activities

Abstract Background Multidrug-resistant bacteria (MDRB) represent a significant global challenge due to their high mortality rates, substantial economic burden, and rapid spread. Traditional triple or quadruple therapies have demonstrated limited efficacy as a result of increasing drug resistance. Thus, it is urgent to develop novel anti-MDRB drugs with high efficiency and low toxicity. Objectives To isolate and identify the dihydrostilbenoids and flavones from the aerial part of Glycyrrhiza uralensis (Fabaceae) and their antimicrobial activities were screened. Materials and methods The aerial part of G. uralensis was extracted with 75% aqueous EtOH. The crude extract was repeatedly isolated by macroporous resin, silica gel, Sephadex LH-20, C18-MPLC, and MCI-MPLC, which were then purified by semipreparative RP-HPLC to obtain monomer compounds. The structures of the isolates were assigned by a combination of optical rotations, UV spectra, nuclear magnetic resonance, and high-resolution electrospray ionization mass spectrometry, and the absolute configurations of compounds 2, 3, and 7 were further confirmed by electronic circular dichroism calculations. Subsequently, we investigated their antimicrobial activities by the broth microdilution method. Results Seventeen previously undescribed phenolic compounds (1–17) and 26 known analogs (18–43), including dihydrostilbenoids, flavones, and dihydroflavones, were identified from the aerial part of G. uralensis. In vitro, antimicrobial bioassays demonstrated that compound 31 displayed the strongest inhibitory effect against 4 drug-resistant Helicobacter pylori strains (MIC = 2–4 μg/mL), comparable to metronidazole (MIC = 1–32 μg/mL). Additionally, compounds 10, 13, and 15 demonstrated bactericidal activity against Staphylococcus aureus (MIC = 4 μg/mL), while compounds 15 and 22 exhibited inactivation effects against Mycobacterium smegmatis, Enterococcus faecium, and E. faecalis (MIC = 4–8 μg/mL). Conclusions These monomeric compounds with antimicrobial activities were isolated from the aerial parts of G. uralensis, providing valuable insights into the potential anti-MDRB properties of its nonmedicinal parts.